mod_status_xml for Apache 1.3

The status XML module is designed to work in a similar way to the
Apache 1.3 mod_status module, allowing a server administrator to find
out how well their server is performing. Instead of HTML output, a XML
page is presented that gives the current server statistics in an easily
readable form. If required this amount of information can be reduced,
which is useful if you are periodically capturing the output for example.

Some browsers (IE6,Mozilla 0.9) are able to perform conversions on XML
data internally; so the module allows you to give the name of a stylesheet
the browser can download and apply to the document. A sample stylesheet
is included that gives an almost identical display to the HTML mod_status
output.

Rather than a patch to the existing mod_status.c file this has been
made into a separate module so that we can extend it in the future to
do more things, and because you don't need mod_status if you have mod_status_xml and a recent browser.